rem 700 pressure signs?

[sundance1972]

Not sure if this is a presseur sign or other problems, but here goes..I recently purchased an older rem 700 in 7mm rem mag that i'm having a bit of a problem with.(Hope i explain this so it makes sense) Went to the range today and had 5 shots where the bolt would lift about 90% of the way, then it seemed to "jam up". A somewhat stiff thump on the bolt knob with the palm of my hand and it would open up the rest of the way and extract the empty shell with no problem. The load that "jammed" was 63 gr 4831 with 160gr accubonds ,yet 64-66grains opened with no problems. I also shot some 160's with up to 69 grains of 7828 with no problems. All the brass looked good, no signs of pressure or primers backing out at all, so i'm a little confused as to what the problem is. On close inspection, it looks like part of the bolt has been hitting the receiver (theres an actual gouge in the receiver, but no marks on the bolt) that i've tried to show in the pics. Has anyone else experienced this,

or have any suggestions as to what it could be?

 

[sunray]

"...stiff thump on the bolt knob..." Hard opening is one sign of excessive pressure.
63 gr of IMR or H4831 is over max. 69 grains of 7828 is 5 grains over max. Bad Ju-Ju is headed your way.
The pictures aren't clear enough to tell what the damage is.

 

[sdeering]

Pressure sign on the primer is not backing out. The primer will lose its radius at the primer /primer hole junction. The more pressure the more it will flatten out filling the entire hole.

A primer backing out is mor of a head space problem.

Is all the brass from the same lot?
Maybe some is softer. I guess if you are over spec. you know what is causing it.
Stephen

 

[Leeper]

This is a not uncommon problem with Remington 700's. The angle of the extractor cam at the root of the bolt handle and that of the camming surface on the receiver don't match up. In addition, remington receivers are fairly soft so the handle soon makes a notch in the camming surface. The answer is to dress both surfaces so they match up better. If one has to remove too much metal to smoth things up, it may be necessary to relocate the handle a bit forward of it's present position on the bolt body to maximize primary extraction after the surfaces have been correctly matched. It's also a decent idea to harden the camming surface on the receiver but this is an option and one with which many 'smiths are uncomfortable.
So, the final answer is, it's probably a rifle problem and not a load problem and it is repairable. Regards, Bill

 

[NormB]

Marks on receiver extraction Cam

The remington bolt handle is harder than the receiver extraction cam. When you bump the bolt to open after an overpressure load it wacks into the cam and flattens/dents it. pretty soon you won't get extraction (backwards pulling on the empty) if you flatten it out.

H4831 is a much faster powder than IMR7828. they are not directly comparable

so 63 gr of 4831 can't be compared to 69gr of IMR 7828.

Get a loading book and back way off your powder amounts.

NormB